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Discussion in 'Amps and Cabs [BG]' started by motherfunker, Dec 29, 2003.

  1. motherfunker


    Apr 29, 2002
    New York
    I was looking over the manual of my newly-purchased Ampeg B100R and I was a bit confused by one thing--it said that excessive GAIN could cause "clipping"...

    ...so the question is, what IS "clipping"? is it bad for the amp? does it not affect it? or does it really not matter...?

    Any help is appreciated.

  2. Trevorus


    Oct 18, 2002
    Urbana, IL
    most bass amps don't like clipping. Preamp clipping can be bad, unless it's made for it. Poweramp clipping is bad. Distortion, is really what it means.
  3. Hollow Man

    Hollow Man Supporting Member

    Apr 28, 2003
    Springfield, VA
    Clipping is when you overdrive your amplifier to a point that it cannot accurately process your signal.

    In other words, when you clip, you're putting a normal sound wave into your amp that is too high for your amp to accurately send to your speakers. Because of this, your amp chops off the peak of your signal to compensate, and send this flat-top (clipped) signal to your speakers. You hear this as distortion.

    Preamp clipping is what happens when your input gain is too high, and most amplifiers can handle it to a certain degree. Clipping in the output stage of your amp, however, is often bad, as your speakers do not like heavily clipped signals.
  4. speakers do more than not like clipping they tend to blow up u fry them if your amp clips to bad. do a search on clipping and you will learn all sorts of great stuff.
  5. Mud Flaps

    Mud Flaps

    Feb 3, 2003
    Norton, MA
    You probably don't have to worry about clipping blowing up your amp. It just makes you sound bad, that's all.

    To stop it, just turn down the volume on your bass.
  6. Ok, clipping of the power amp probably will not blow up your amp but it will blow up your speakers. See it as putting a DC voltage on a speaker. For a DC voltage the speaker resistance is very low (about 2ohms). And this will heat up the speaker very fast ....till it burns.
    As the preamp and the poweramp are only AC coupled, preamp clipping will not do any harm. (will ofcourse result in the overdrive sound)
  7. how do you know whether it's the preamp or the poweramp that clips, when they're in the same head? :/
  8. Good question, a clipping led for the preamp is very usefull for this but not all amps have one.

    Some combo's I know have some kind of a compressor which enables when the poweramp saturates (clips) At this point the compressor compresses the input signal down to the nominal level.

    Besides this think the rule should be:

    1) Make your tone settings in the eq section.
    2) Play the bass as loud as you can at low master volume and turn up the gain to the point it just begins to distort. (half way?) Now the clipping level of the pre-amp is reached. The level of the gain is now optimal for the signal flow (it has the full line voltage swing)

    3) Turn up the volume, when now the point reaches that the amp is sounding distorted you know the poweramp clips. So turn it down.

    Please note that when changing the tone settings the clipping point of the preamp also changes. for example increasing bass or mid will increase for those frequencies the preamp output.

    Well maybe it helps.

  9. So if I run my preamp barely clippin and have my master wide open and it sounds great a little to loud for practice but no distortion. How would you find power amp cliiping besides just listening for distortion?
  10. I think the only way is to listen. Ofcourse you can do some measurements but don't think you want to do that.

    I would advice to keep at least 25% headroom on whatever amp. So don't open the volume to its max. This because your play always will be dynamic. For that you need headroom.

    Well at least that is my experience.
  11. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    A clipped signal is not DC.
  12. Welcome in the discussion Bob. Love those one liners....

    My statement was indeed not complete.
    I should have stated that clipping can cause drift or a DC offset in the output signal.

    In another discussion in this forum (and I see you found it) we discussed more about the question why clipping is dangerous.
  13. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    That's not what you were hinting. You implied that clipping = DC.

    Most modern pro amps are AC coupled and have protection against DC on the output.
  14. Right, well anyway before we start over again.
    A recent discussion about this subject can be found here here and you are right, clipping is not equal to DC.

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